Injury is a leading cause of death and disability among older adults, with a disproportionately high morbidity, mortality, and cost. As the older adult population rapidly expands, the patient and public health burden will similarly expand unless we significantly improve trauma care for these patients. The Field Triage Decision Scheme, developed by the American College of Surgeons, guides ambulance-based emergency medical services (EMS) providers when determining whether to transport injured patients to a trauma center. The current Decision Scheme poorly considers the physiological and clinical challenges posed by aging when guiding the management of injured older adults. It does not account for unique, age-specific factors such as pre-existing co-morbidities, use of multiple medications, and compromised resiliency for responding to physical stressors which can complicate older adults' clinical presentation and outcomes. This failure is known to lead to under-triage, and may lead to over-triage. Under-triage of patients will increase their risk of morbidity and mortality, whereas over-triage of patients adds to the cost of care and emergency department crowding, and decrease the responsiveness of the emergency care system. Our overall goal is to assess the current Field Triage Decision Scheme's ability to identify older adults who need trauma center care and determine whether creating guidelines specifically for older adults would improve its accuracy. We will use existing data from a prospective, multi-center study of 11,892 injured EMS patients enrolled in the emergency department and followed to hospital discharge. In our proposal, we specifically aim to: 1) compare the classification accuracy of the Decision Scheme to identify patients who require trauma center care between younger and older adults; 2) derive a new triage decision scheme specifically for older adults; and 3) compare the classification accuracy of the new, older adult-specific decision scheme to the Decision Scheme in place. This study will rigorously derive the first comprehensive, age-specific decision scheme to identify older adults needing trauma center care. Our findings will allow us to apply for R01-level funding to prospectively conduct a multi-center validation of the derived decision scheme and to inform the protocols used by EMS providers when caring for injured older adults.